Stress; when a good thing goes bad | Dr Natalie Riddell | TEDxGuildford

Summary

Stress is more than an emotion; it affects our immune system, potentially leading to illness. Dr. Natalie Riddell explains how stress hormones, adrenaline and cortisol, can alter immune cell behavior and disrupt circadian rhythms, impacting health. Chronic stress can exhaust the immune system, increasing susceptibility to diseases and possibly accelerating aging. Social support and stress management techniques are crucial for maintaining immune health and overall well-being.

Takeaways

• 🧬 Stress has a direct impact on our immune system, influencing our response to infections and cancers.
• 🌡️ During stress, hormones like adrenaline and cortisol are released, which can alter the number and function of immune cells in our body.
• 🌙 These hormones follow a circadian rhythm, helping with immune activation during the day and tissue repair at night.
• 🔄 Chronic stress can disrupt this rhythm, potentially leading to health issues.
• 📊 The Holmes and Rahe stress scale demonstrated a correlation between life stressors and the likelihood of illness.
• 🏥 In 2006, stress was identified as the second most common cause of ill health in the UK, leading to significant workdays lost.
• 🧠 Our 'stone-age brain' might not be well-adapted to cope with modern stressors, leading to a less effective stress response.
• 🛡️ Acute stress can temporarily boost the immune system by increasing the number of immune cells, which is beneficial for short-term survival.
• 🔄 Chronic stress, however, can lead to a loss of immune balance, increasing susceptibility to infections, cancers, and inflammatory conditions.
• 🤝 Social support and interventions can improve immune function and overall well-being, suggesting the importance of community and mental health resources.
• 🧘‍♂️ Mindfulness and emotional intelligence training can help manage stress and enhance cognitive function and well-being.

Q & A

What is the main focus of Natalie Riddell's research?

Natalie Riddell's research focuses on how stress can affect the immune system, particularly how it changes the way we respond to infections and cancers.

What are the two hormones released during stress and how do they impact the immune system?

During stress, the hormones adrenaline and cortisol are released. They can directly act upon the immune system, impacting its function by changing the number of cells in our blood and organs and altering how these cells respond and recognize infections and cancers.

How do the levels of adrenaline and cortisol change throughout the day?

The levels of adrenaline and cortisol change throughout the day due to their circadian rhythm, which promotes immune activation during the day for protection and supports tissue repair and regeneration overnight when we are at rest.

What is one consequence of stress on the circadian rhythm of hormones?

One consequence of stress is that it can alter the circadian rhythm of hormones, which can then impact health by disrupting the natural cycle of immune system activation and tissue repair.

What is the Holmes and Rahe stress scale, and how does it relate to health outcomes?

The Holmes and Rahe stress scale, developed in the 1970s, assigns a stress score to various life events and tallies these to predict the likelihood of illness. It demonstrates an association between stress and health outcomes.

How does stress affect society according to the Health and Safety Executive's findings?

According to the Health and Safety Executive, stress was the second most commonly reported reason for ill health in 2006, leading to 45% of all workdays lost due to ill health, equating to 11.7 million sick days.

What is the evolutionary psychologist's theory regarding the human brain's adaptation to stress?

The theory suggests that humans have a 'stone-age brain,' meaning our brain hasn't adapted enough to modern-day stresses, potentially leading to a maladaptation of our stress response to contemporary life.

How did Richard S. Lazarus define stress in the 1960s?

Richard S. Lazarus defined stress as an association between appraisal and coping, where a stressful event leads to an assessment of our ability and resources to deal with it. If we believe we cannot cope, we become stressed.

What is the role of the sympathetic nervous system during stress?

The sympathetic nervous system is activated during stress, leading to a fight or flight response. It innervates many organs, including those of the immune system, and stimulates the adrenal glands to release adrenaline and cortisol.

How does acute psychological stress affect the immune system?

Acute psychological stress can boost the immune system by increasing the number of immune cells in the peripheral blood, promoting protection against infections and potentially enhancing survival.

What are the three stages of the general adaptation syndrome described by Hans Selye?

The three stages of the general adaptation syndrome are: 1) the stress response with a fight or flight reaction, 2) a state of adaptation where the body builds resistance to stress, and 3) exhaustion of the system leading to illness if stress becomes chronic.

How does chronic stress affect the immune system and potentially lead to premature aging?

Chronic stress disrupts the balance of the immune system, leading to decreased immune protection and increased inflammation. This can result in the premature aging of the immune system and an increased incidence of infections, malignancies, and inflammatory conditions.

What are some strategies mentioned to combat the negative effects of stress?

Strategies to combat stress include increasing social engagement, providing support networks, engaging in mind-body therapies, teaching mindfulness, and improving emotional intelligence. These can help improve immune function and overall wellbeing.

Outlines

00:00

🔬 The Impact of Stress on the Immune System

Natalie Riddell, a lecturer in immunology and ageing, discusses the profound effects of stress on the immune system. She explains that stress isn't just a fleeting emotion but has tangible consequences on health, particularly through its influence on the immune response to infections and cancers. During stress, the body releases adrenaline and cortisol, hormones that can directly affect the immune system by altering the number and function of immune cells in the blood and organs. These hormones follow a circadian rhythm, meant to protect us during the day and facilitate tissue repair at night. However, chronic stress can disrupt this rhythm, leading to health issues. Riddell highlights that stress is not only a personal burden but also a societal concern, as evidenced by the significant number of workdays lost due to stress-related illnesses. She also touches on the evolutionary perspective, suggesting that our 'stone-age brains' may not be well-equipped to handle modern-day stressors, which could exacerbate the stress response.

05:03

🏃‍♂️ The Fight or Flight Response and Its Effects

This section delves into the physiological changes that occur during stress, focusing on the activation of the sympathetic nervous system and its widespread effects on the body. The sympathetic nervous system, responsible for the fight or flight response, prepares the body for action by increasing heart rate, respiratory rate, and energy production. This response is beneficial in the short term, enhancing physical capacity to deal with stressors. The adrenal glands are also stimulated, releasing adrenaline and cortisol into the bloodstream, which then act on various organs, including those of the immune system. Every cell of the immune system is affected by stress, with processes like cell development in the bone marrow and immune response initiation in lymph nodes being altered. The acute psychological stress response is shown to boost the immune system temporarily, increasing the number of immune cells in the blood to combat potential infections. However, this response was not designed for long-term activation, and chronic stress can lead to a loss of immune balance, decreased protection, and increased inflammation, potentially contributing to premature ageing of the immune system.

10:04

🤝 Combating Stress Through Social Support and Intervention

The final paragraph emphasizes the importance of social support and intervention in mitigating the negative effects of stress. It discusses how caregivers with little social support exhibit a suppressed immune system, which is evident in their reduced response to vaccinations. However, providing a support network or engaging in therapies like mind-body practices can improve their immune function. The speaker suggests that increasing social engagement and providing support networks for isolated individuals could enhance overall well-being. The paragraph also underscores the value of teaching resilience and stress management, such as mindfulness and emotional intelligence, to improve cognitive function and well-being. The speaker calls for a change in societal attitudes towards stress, advocating for its recognition as a normal physiological response and for policymakers to prioritize stress management to prevent the associated health issues, such as heart disease and dementia. The conclusion is a call to action for managing stress and fostering resilience to promote health and well-being across all age groups.

Keywords

💡Stress

Stress is a state of mental or emotional strain or tension resulting from adverse or demanding circumstances. In the video, stress is portrayed as more than just an emotion; it has physiological consequences that can affect the immune system and overall health. The speaker discusses how stress can alter the immune response, making individuals more susceptible to infections and diseases, thus emphasizing the importance of understanding and managing stress.

💡Immune System

The immune system is a complex network of cells, tissues, and organs that work together to defend the body against harmful pathogens and maintain health. The video highlights how stress can directly impact the immune system by changing the number and function of immune cells, which can lead to a compromised ability to fight infections and cancers. The immune system's response to stress is a central theme, illustrating the intricate relationship between mental health and physical well-being.

💡Adrenaline

Adrenaline, also known as epinephrine, is a hormone and neurotransmitter that is released during stress in response to a perceived threat. It prepares the body for a 'fight or flight' response by increasing heart rate and blood flow to muscles. In the context of the video, adrenaline is one of the hormones released during stress that can directly act upon the immune system, potentially altering its function.

💡Cortisol

Cortisol is a steroid hormone that plays a key role in the body's response to stress and in regulating various processes in the body, including metabolism, immune response, and inflammation. The video discusses how cortisol, like adrenaline, can impact the immune system by changing the way immune cells respond to infections and cancers, which can have significant health implications.

💡Circadian Rhythm

Circadian rhythm refers to the body's internal clock that regulates the sleep-wake cycle and repeats roughly every 24 hours. The video mentions that the levels of stress hormones like cortisol have a circadian rhythm, which is thought to promote immune activation during the day for protection and tissue repair at night. Stress can disrupt this rhythm, potentially leading to health issues.

💡Fight or Flight Response

The fight or flight response is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It is a part of the acute stress response and involves the activation of the sympathetic nervous system. The video explains that this response prepares the body to either confront the threat or escape from it, which is beneficial in the short term but can be detrimental if the stress becomes chronic.

💡Inflammation

Inflammation is part of the immune response to harmful stimuli, such as pathogens, damaged cells, or irritants. It is a protective mechanism that involves immune cells and molecules to eliminate the cause of cell injury and initiate tissue repair. The video discusses how chronic stress can lead to increased inflammation, which can exacerbate inflammatory conditions and contribute to various diseases.

💡Sympathetic Nervous System

The sympathetic nervous system is a part of the autonomic nervous system that prepares the body to react to stress and emergencies. It is often referred to as the 'fight or flight' response system. In the video, it is mentioned that this system innervates many organs, including those of the immune system, and plays a crucial role in the body's physiological adaptations during stress.

💡Adrenergic Receptors

Adrenergic receptors are a class of cell surface receptors that respond to the binding of hormones like adrenaline and noradrenaline. They are involved in the regulation of various physiological processes, including the immune response. The video explains that immune cells express these receptors, making them responsive to adrenaline, which can influence their function during stress.

💡Glucocorticoid Receptors

Glucocorticoid receptors are intracellular receptors that bind to glucocorticoids, such as cortisol. They play a role in regulating immune responses and inflammatory processes. The video mentions that immune cells express glucocorticoid receptors, which allows them to be influenced by cortisol, potentially altering their behavior in response to stress.

💡Chronic Stress

Chronic stress refers to long-term, ongoing stress that can have detrimental effects on health. In the video, chronic stress is contrasted with acute stress, highlighting how it can lead to a loss of immune system balance, decreased immune protection, and increased inflammation. The speaker argues that chronic stress can contribute to the development of various diseases and conditions, emphasizing the importance of stress management.

Highlights

Stress is not just a fleeting emotion but has lasting effects on our health.

Natalie Riddell's research focuses on how stress impacts the immune system.

Stress can change our response to infections and cancers.

Understanding stress's effect on immunity may lead to better health outcomes.

Adrenaline and cortisol are hormones released during stress that directly affect the immune system.

Hormone levels fluctuate with a circadian rhythm, influencing immune activation and tissue repair.

Stress can disrupt the circadian rhythm, potentially impacting health.

The Holmes and Rahe stress scale correlates life events with the likelihood of illness.

In 2006, stress was the second most common cause of ill health in the UK workforce.

Daily life events, such as traffic or forgetting names, can trigger a stress response.

Social media exposure may exacerbate stress due to constant social comparison.

Our 'stone-age brain' may not be well-adapted to modern stressors.

Richard S. Lazarus defined stress as the relationship between appraisal and coping.

The sympathetic nervous system activates during stress, increasing heart rate and energy production.

Adrenaline and cortisol affect every process of the immune system.

Acute psychological stress can temporarily boost the immune system's ability to fight infections.

Chronic stress can lead to a loss of immune balance, increasing inflammation and disease risk.

Social support and therapy can improve immune function and overall wellbeing in stressed individuals.

Stress management and teaching resilience are crucial for promoting health and wellbeing.

Transcripts

Translator: esther premkumar Reviewer: Robert Tucker

Stress can get under our skin,

it's not just a feeling or an emotion that passes over us,

stress has consequences.

My name is Natalie Riddell.

I'm a lecturer in immunology and ageing,

and I study how stress can affect the immune system.

I'm interested in how stress can change the way

that we respond to infections and cancers.

And I believe that if we can understand how stress changes the immune system,

and how it regulates the immune system,

we may be able to manipulate and control our immune response to stress.

And this may help us promote better health outcomes.

During stress, two hormones are released: adrenaline and cortisol.

And both these hormones can directly act upon the immune system.

And this means that these hormones can impact upon health.

They can do many things to the immune system,

including changing the number of cells that are in our blood,

or in our organs,

and also changing the way

that these cells respond and recognize things such as infections and cancers.

The levels of these hormones change throughout the day,

depending on what time of day it is.

They have circadian rhythm,

and this is thought to promote immune activation during the day,

which will protect us and promote tissue repair and regeneration overnight

when we are at rest.

And one of the consequences of stress

is that it can alter this circadian rhythm,

and this can then impact health.

So, why do we think that stress is bad?

Most people have either been stressed their self

or know someone who has been stressed,

who has then become ill.

But there is also scientific evidence to support this.

In the 1970s, Holmes and Rahe developed a stress scale.

They took over 14 normal life events,

some of them quite major life events,

like losing a loved one or otherwise relationship breakups,

and some not so major life events such as Christmas.

They gave each of these different stresses a stress score,

they tallied up the amount of stress

that a person had experienced in the previous year,

and this was able to predict

the likelihood of illness in those individuals.

So, this really showed

that there is an association between stress and health outcomes.

And stress doesn't just affect the individual,

it also can affect and have a huge impact on society.

The Health and Safety Executive,

who monitor and regulate the health of the workforce here in Great Britain,

found in 2006

that the second most commonly reported reason for ill health

was because of stress.

This equated to 45% of all workdays lost due to ill health.

That's 11.7 million sick days.

And these numbers could actually be a lot larger

because most people won't actually report

that the reason that they are off work is because of stress.

Because there is such a stigma associated with stress and mental health.

And even quite mundane daily life events can cause stress.

Today, I was stuck in traffic and I became quite irritated.

I also get really embarrassed if I forget somebody's name.

And even the social expectations that we put upon ourselves,

and put upon each other,

can cause a stress response.

And this is becoming ever more prevalent in a world of social media

where we're constantly exposed 24/7.

And each of these stresses, although very different,

causes the same stress response.

There is one theory from evolutionary psychologists

that we have a stone-age brain.

This doesn't mean that our brain has not evolved at all since the stone age,

just that it hasn't adapted enough.

And this could be true for the stress response.

You can imagine that the types of stresses we face in the modern world

are very different to our cavemen ancestors.

So, it is possible that our adaptation to stress

does not serve us well

when we are considering the modern day stresses.

So stress, it's a big thing.

It's an important part of our biology.

So, how can we define stress?

In the 1960s, the psychologist Richard S. Lazarus

defined stress as being an association between appraisal and coping.

So, when a stressful event occurs,

we assess our ability and our resources to deal with that stressful event.

If we believe that we can cope, then everything is fine.

But, if not, we become stressed.

Put simply, it's a situation or an event

that exceeds or is perceived to exceed our ability to cope.

And this results in an emotional response and a biological adaptation,

such as anxiety and activation of the sympathetic nervous system.

So, stress is something of an event that is out of our control,

that we feel we can't cope with, and causes a biological adaptation.

Our biological adaptation is activation of your sympathetic nervous system.

And, as you can see from this diagram here,

the sympathetic nervous system innervates many organs throughout the body.

This means that during stress many physiological adaptations occur,

including an increase in our heart rate, an increase in respiratory rate,

and also greater energy production.

And this all allows increased physical capacity

for the individual to cope with whatever the stressor is.

So, it's a good thing, it's our fight and flight response,

it promotes the survival of the individual.

We also see stimulation of the adrenal glands

and this results in the release of the hormones adrenaline and cortisol.

And these are released directly into the blood

where they are able to then circulate and act throughout the body.

Each and every one of the organs of the immune system are innervated

by the sympathetic nervous system.

This means they are under regulation of the sympathetic nervous system

during stress.

Also, each of the cells of the immune system

expresses adrenergic receptors and glucocorticoid receptors.

This makes them responsive to adrenaline and cortisol.

For example, every process of the immune system

is affected by stress.

So, for example, the development of newer cells in the bone marrow

is altered during stress.

Also, the initiation of immune response to stress in the lymph nodes is affected.

And the cells, when they are out in the peripheral tissues,

such as the lungs, or the guts or the skin,

they are also affected by adrenaline and cortisol.

So, considering that the stress adaptation response

is meant to be a beneficial response that promotes our survival,

we would expect the immune system response to stress

to also promote survival of the individual.

And that is indeed what happens during acute psychological stress.

So stresses that last just for minutes or hours.

So, as I'm stood here in front of you today,

I'm having a stress response.

My heart rate is through the roof, adrenaline is rushing through my veins,

and so are a very large number of immune cells.

As you can see from this graph, during acute stress -

this data was from individuals that were given a 10 minute talking task,

or doing a 10 minute talking task -

you can see that the stressor almost more than doubled

the amount of immune cells present in the peripheral blood,

compared to blood samples taken at base line

when the person wasn't stressed.

And as soon as the stress finishes,

the number of immune cells in the blood returns to normal.

And what my work and work by others has shown

is that not all cells respond during stress.

Only the soldiers of the immune system respond.

These are the cells that are able to migrate into the inflamed tissues,

and, once there, they can immediately eradicate

any infections they come in contact with.

So acute psychological stress does boost our immune system.

It promotes a protection against infections.

And this, we believe, will promote the survival of the individual.

However, most common day stressors

don't actually, or, nowadays, do not,

come with the threat of infection and injury.

So, how does the physiological response to stress manifest in the modern era?

Imagine that an individual has an underlying and inflammatory condition.

When they become stressed,

they see this increase in the soldiers of their immune system surveying the body.

This could aggravate the inflammatory condition that they have.

And what happens if the stress doesn't last only for minutes or hours?

What if it goes on for weeks, or months, or even years?

The stress adaptation response did not evolve to last for that long

and, consequently, it can't.

In the 1930s, Hans Selye, recognized this,

and he described three stages of the general adaptation syndrome.

The first stage was the stress response.

This is when the individual has a fight and flight response.

But we can't maintain this level of excitement for a long time.

We then move into a state of adaptation.

This is where the body builds up resistance to the stress.

And finally, if the stress becomes chronic,

then we become exhausted, the system becomes exhausted.

And it's when this exhausted state is reached that we become ill.

The immune system is a delicate balance

between immune protection against infections and cancers,

and immune regulation which will prevent inflammatory disorders:

it stops self-harm, it stops an overzealous immune response,

so it will stop autoimmune diseases.

What we see during chronic stress is the worst of both worlds.

We see a loss of this balance,

and we see decreased immune protection, and we see increased inflammation.

And this is very similar to what we see within old individuals

when we look at their immune system.

So this may suggest that chronic stress

can also promote premature ageing of the immune system.

So, we believe that chronic stress,

via this loss of normal immune regulation and by ageing the immune system,

may mediate the association

between stress and increase incidences of infections, malignancies,

and also inflammatory conditions.

So, chronic stress is a good thing that has gone bad.

The stress adaptation response was originally a good thing,

but when it becomes chronic, it becomes a bad thing.

But we can't stop stress, we can't stop it happening.

But, as stress only occurs

when an individual perceives that they cannot cope,

it may be able to teach resilience to the threat.

And our best weapon against stress is social intervention.

In studies of caregivers with spouses with dementia,

we found that their immune system is suppressed.

If you give caregivers a vaccination, they have a reduced immune response.

But the level of this reduction is directly correlated

to how much social support they feel they have.

Those individuals with very little social support

have a worse immune response to vaccination

than those who have higher social support.

And in the individuals that have very little social support,

if you actually provide them with a support network,

their immune system and their immune response improves.

Or if you engage them in therapy, such as mind-body therapies,

this can also improve their immune response.

So we really have a window here

where we can increase social engagement at work

or we can provide support networks to isolated vulnerable people in society.

And we may be able to improve their immune function

and improve their overall wellbeing.

Usually, prevention is better than cure.

And one way we can try to prevent stress

is by teaching people to understand and manage their stress.

For example, teaching people mindfulness

can actually improve their cognitive function

and their overall wellbeing.

And this has been demonstrated in student populations, military personal,

and also in cancer patients.

And teaching emotional intelligence,

the importance of it is now becoming recognized,

so it's now being taught in some schools.

And the Healthy and Safety Executive

has placed stress management as one of their top three priorities.

And this is because of the condemning figures I showed you earlier,

demonstrating that stress

is now the second most common cause of work related illness.

And we need to talk about stress.

We need people to understand

that the stress response is a normal physiological response,

and, hopefully, this will help remove the stigma associated with stress.

And we need to engage the policy makers.

We know that the physiological response to chronic stress

is causing ill health in individuals.

It's associated with some of the most common diseases

facing the modern world,

such as heart disease and dementia.

These are some of the biggest killers currently in society.

But despite this,

and despite the fact that stress management is easy and affordable to do

compared to other medical in[ter]ventions,

we don't try to manage stress nearly enough.

So we really need to encourage the policy makers to take stress seriously

and put it upon the agenda.

I truly believe that by managing stress and teaching people resilience,

we will be able to promote health and wellbeing

in everyone from children right through to the elderly.

And this will help people be the best they can and feel the best they can.

Thank you very much for listening.

(Applause)